328 THE ALCALIGENES DYSENTERY TYPHOID 



protein under these conditions is left unattacked except for minute 

 amounts necessary to supply the nitrogenous requirements of the 

 organism. The acids formed are chiefly lactic acid, together with 

 smaller amounts of formic acid. 1 Indol or phenols are not formed 

 in ordinary media, but Peckham 2 has shown that indol may be pro- 

 duced in protein media of special composition. 



The essential cultural characters of B. typhosus are indicated in 

 the table on page 316. Culturally Bacillus typhosus is relatively 

 inert; it does not produce proteolytic enzymes which liquefy gelatin, 

 blood serum or fibrin. A fat-splitting ferment has been demonstrated 

 in autolyzed typhoid bacilli by Wells and Corper. 3 An esterase 

 which liberates butyric acid from ethyl butyrate is detectable in sterile 

 filtrates of plain and dextrose broth cultures of the organism. 4 



Typhohemolysin (typholysin) . Castellani, 5 and E. Levy and P. 

 Levy 6 have found that filtrates of (sugar-free) broth cultures of typhoid 

 bacilli are hemolytic. They appear to have demonstrated specific 

 antihemolytic properties in the blood of animals injected with hemo- 

 lytic filtrates, thus meeting the objection that the hemolysis might be 

 due to the alkalinity of the medium itself. There is no evidence at 

 present which would suggest that this hemolysin plays any impor- 

 tant part in typhoid infections of man. The typholysin is relatively 

 thermostabile. 



Toxins. A soluble toxin has never been satisfactorily demon- 

 strated among the products of growth of the typhoid bacillus, and 

 the consensus of opinion at the present time is in favor of the view 

 that the principal toxic substance of the organism is an endotoxin. 

 The endotoxin has been studied with special thoroughness by Mac- 

 Fadyen and Roland, 7 and Besredka. 8 It has been obtained in various 

 ways: by grinding the organisms with sand, by freezing in liquid air 

 and triturating, or by autolysis of the bacilli in sterile distilled water. 

 Relatively small amounts of endotoxin obtained by any of these 

 methods will usually kill guinea-pigs. No antitoxin has been produced 

 in the sera of animals inoculated with gradually increasing amounts 

 of this endotoxin. 



1 Kendall, Jour. Med. Research, 1911, xxiv, 411; 1912, xxv, 117. Boston Med. and 

 Surg. Jour., 1911, Ixiv, 288. Kendall, Day and Walker, Jour. Am. Chem. Assn., 1913, 

 xxxv, 1214. 



2 Jour. Exper. Med., 1897, ii, 549. 3 Jour. Infec. Dis., 1912, xi, 388. 



4 Kendall and Simonds, Jour. Infec. Dis., 1914, xv, 354. 



5 Lancet, February 15, 1902. 6 Cent. f. Bakt., 1901, xxx, 405. 



7 Cent. f. Bakt., Orig., 1903, xxxiv, 618, 765; MacFadyen, ibid., 1903, xxxv, 415. 



8 Ann. Inst. Past., 1905-1906. 



